When new gadgets are made, almost everyone wants to see what's inside, including myself. The case is made of anodized aluminum with those 2 plastic rivets holding the PCB in place. Well after getting my fingernail under the rivet top, I found out that I could remove both of them, so I took out the PCB. Take a look at the rivet and some shots of the PCB.
I'm not an electrical engineer so I really can't explain this any further than to say, the design is based on a PIC Micro Controller 12C508A.
Hooking up the Power Down Protector is really straight forward. The first thing you need to do is make sure WOL is enabled in your BIOS. I had it disabled and the P.D.P would not function properly. Once that is turned on, the minimal installation is to connect to your WOL header on your motherboard (Asus Cusl2-C used), then connect to your fan header (I'm using my front intake fan's header for this test), and then connect the fan cable to the Power Down Protector. I am using a Sunon 92mm (49.5cfm @ 34.5db/a @ 2.8 watts) fan for the test as it was handy and not installed. Note: Based on Amperage requirements, I was unable to test with 2 92mm fans. Here are the images in order: